Well depth recording



1943- J. :r. HAYWARI": 2,326,219

WELL DEPTH RECORDING Filed Dec. 30, 1939 3 Sheets-Sheet 1 v INVENTOR. 12-J. YTHAYWARD if? 30 ATTORNEYS.

Aug. 10, 1943. J. T. HAYWARD WELL DEPTH RECORDING Filed Dec. 30, 1939 3Sheets-Sheet 2 D 4 m mm 40. MW n 9 1 m 1 7 H w E vnm J w E w j m 1 ATTORNEYS.

Patented Aug. 10, 1943 UNITE-D STATES PATENT. OFFICE WELL DEPTHRECORDING John T. Hayward, Tulsa, Okla. Application December 30, 1939,Serial No. 311,805

16 Claims. -('o1. 33-134) This invention relates to a chart drive andparticularly to a driv mechanism for driving a depth recording chartfrom the movements of drilling tools in a well.

In the development of modern well drilling methods, particularly rotarydrilling, wherein a drilling fluid, such as mud fluid, is circulated ofthe traversed strata may be readily determined directly from the mudstream during drilling and'the various strata logged at their respe'ctive depths. In these'methods, as well as in connection with other;operations about 'a drilling well, it is highly important that theprogress of the drill and depth ofthe well be known at all times withinvery narrow limits of accuracy. In

logging particularly, it is important that those this system acontinuous accurate record of the depth of the well can be made on whichcurves characteristic of the traversed strata can be traced in properrelationship to the depth.

The system of this invention employs a novel iorm or drive mechanismwhereby only those movements of the drilling tools which representprogressively increasing depth oi the well are employed to drive a stripchart carrying footage indications thereon. It will be obvious to thoseskilled in the art that in the ordinary methods of rotary drilling, thedrilling tools make numerous movements in and out of a well which arenot directly representative of increasing depth of the well. Forexample, the drilling string must be frequently withdrawn from andinserted into the well when changing bits, when adding new joints ofdrill pipe, when removing defective sections of the drill pipe, whenreaming dowm. to a previously attained depth, and for various otheroperations. It is a principal object, therefore, of this inventiontoprovide an apparatus whereby only those movements of the drillingtools which are representative of progressively increasing depth areselectively employed to drive a chart bearing the depth record.

Another object is to provide a novel form of selective transmission forthe'aforesaid movements from the drilling tools to the depth recordingchart.

Still another object is to provide a novel form of transmissionemployingco ting devices for selecting those movements of the drilling toolswhich are transmitted to a depth reading chart.

A further object is to provide in conjunction with the transmission,apparatus of this invention, additional mechanism for mechanically in-'troducing therein correction factors to compensate for-wearing of theparts and for changes in length of portions of the drilling tools.

An additional object is to provide a novel form of connection betweenthe drilling tools and the transmission mechanism proper of thisinvention.

()ther objects include the provision of electrically operated controls,actuated by the transmission mechanism for selecting the desiredmovements to be transmitted to the chart; for

providing either audible or visible signals, or both,

at certain stages in the operation of the device; to controltheoperation of the pens which draw the various curves on the chart; andfor numerous other operations which are directly related to the progressof the"drill in the well.

Variousother objects. and advantages of my new invention will becomeapparent to those skilledin the art from the following detaileddescription when read in conjunction with the accompanying drawingswhich illustrate a pre-' ferred form of this invention and severaluseful embodiments thereof. In the drawings: I Fig. 1 is a generalassembly showing a drilling rig and the chart drive mechanism .connectedthereto.

Fig. 2 is a sectional detail taken along line 2-2 of Fig. l to betterillustrate a novel form ofconnection between the drill rig and th chartdrive mechanism.

Fig. 3 is a detail in perspective of the connection between themechanism. Fig. 4 is an enlarged assembly of the chart drive mechanismproper.

drill tools and the chart drive Fig. 4. ;-Fig. 7 is a modified" form ofone. of the parts of the chart drive mechanism.

Fig. 8 is an assembly similar to Fig. 4 but including electricalcircuits and connections emloyed'in othermodifications of thisinvention.

Figs. 9 and 11 are details of the apparatus illustrated in Fig.8. Fig/10is a sectional view taken along line lii'i0 of Fi 9, and

Fig. 12 is a simplified and more or less symbolicrepresentation of aform of selective transmission included in this invention. j Referringto the drawings and to Fig. 1 in particular; a conventional derrick it ishown mounted over a well 12. The derrick is equipped with the usualcrown block pulley it from which is suspended a conventional travelingblock it by means of cables i8. The drilling string 20, of conventionaloonstructiomis suspended from the hook 22 carried by the travelingblock. The

drilling string includes the usual water swivel Figs. and s are detailsof the apparatus or and the traveling block iii are known, although onlya single loop is shown, then by simple calculation, the relationship ofthe vertical movement in feet, of the traveling block l6 and, therefore,of the drilling string to the rotations of the pulley I4 can be easilydetermined. By properly proportioning measuring wheel II in relationshipto the diameter of pulley i4, one turn of wheel H can be made to measureany 24, to which is attached the ordinary Kelly joint 26 which is inturn connected to, the usual Jointed hollow drill pipe 28 carrying adrill bit 30 at its lowerend. The drilling string extends through theusual rotary-table 32 which rotates the drilling string by turning theKelly joint in'the usual way.

Since all vertical movements of the drilling string20 in well i2necessarily reslllt'in corresponding vertical movements of travelingblock it, and these in turn result in corresponding rotary movement ofcrown block pulley it through the movements of cables i8 about thepulley, the latter provides a convenient take-off connection fortransmitting the vertical movements of the,

traveling block and drilling string to suitable recording apparatus tobe later described. A convenient form of take-ofi connection to pulleyit is shown in enlarged detail in Figs. 2 and 3 particularly. Thisconnection consists of a measuringwheel ii mounted .on an axle it whichis suitably Journalled in the forks of ayoke i5 which is in turntcarriedby one end of an arm I! which has its other end rotatively mounted onshaft i9 I which is fixedly attached to the beams 2i forming apart ofderrick crown structure. The meas-' uring wheel H is arranged to runinside the groove 23 of crown block pulley i4 and the side desiredlength of vertical movement of the drilling string. A convenientproportion is one wherein each turn of measuring wheel Ii represents onefoot of vertical movement of the drilling tools.

It will be understood that numerouseother measuring devices may be usedin place of that described. Another form which may be used isdescribedin detail in my U. S Patent No. 2,166,212, dated July 18,1939.

Axle I3 of the measuring wheel I i is connected by a flexible shaft 29,of conventional construction, to the armature of the drive motor SI of aI self-synchronous transmission system, the function of which is wellknown in the electrical art and is commonly. referred toss a "Selsynsystem. -Thus each turn of wheel ll pro gluces one rotation of thearmature of driver motor 3| which in turn synchronously transmits thisrotation electrically through leads 33 to the armature of the drivenmotor 35 of the Selsyn system, which correspondingly rotates thearmature shaft 86 on which is mounted a conical smooth surfaced drivepulley 38. 15y the aforedescribed arrangement of apparatus, it will beseen that means edges of wheel ii are held inclose frictional contactwith the adjacent sides of groove 23 by pressure applied through .a coilspring 25 which has oneend attached to'an intermediate portion of arm l1and the other to one of the beams 2| at a point beneath arm." (see Fig.3). The peripheral surface .ofmeasuring wheel il has a groove 2-I.-topermit the wheel to clear cable i8 w ch is threaded in. pulley 14. Bymounting me suring wheel II to run inside the groove 28 of pulley ll, avery efiicient drive connection is provided from pulley I4 to measuringwheel Ii,

since the sides of groove 23 are ordinarily mak shined surfaces and arek t smooth by the rubbing action of the steel cable l8. By accuratelymachining the side edges of wheel ii a very positive frictional contactcan thus be maintained between the pulley and the wheel. Spring 2!provides ajyieldable hold-down which'permits some relative movementbetween the contacting members'while' maintaining positive contact be-,tween'them. a

has been provided whereby all the vertical move- ,7

ments, in either direction, of traveling block l8, and of the drillingstring 20 when suspended therefrom, are translated into rotation in thecorresponding direction of Shaft 36 and pulley 38, each rotation ofwhich will represent one foot of vertical-movement of the travelingblock or of the drilling string where measuring wheel II has been soproportioned that each turn of this wheel corresponds to one foot ofvertical movement of the drilling string. Also, the rotations of shaft36 and pulley 38 are now available for connection to a strip recorderchart 40, of more or less conventional form, by mean of a novel form ofselective transmission apparatus which .forms one of the importantfeatures of this in-.

vention. v The selective transmission mechanism of this inventionincludes a main drive shaft 42 which shaft is connected by a sprocketand chain drive 52 to a first countershaft 54 which is-connected to arevolution counter 56 of more or less conventional construction. Drivenshaft 50 is connected by a sprocket and chain drive 58 to a secondcountershaft 60 which is connected to a tension forminga stub shaft64,1, which-is consecond revolution counter 82. Countershaft 60 extendsthrough the case of counter 82. the ex- I nected by gear connections;designated generally by the numeral 6 6, ton suitable drive forchart l0.Countershaft 60 is provided with a'fr'iction brake, designated generally88, the functionloi which will be explained'in greater detail herein-Since the diameter of pulley I4 is fixed and the number ofables'threaded between the pulle after The end of main drive shaft 42anterior to auxiliary differential carries a smooth cone shaped drivepulley 10, which is positioned adiacent to drive pulley 38 but slopes inthe opposite direction to the latter. conventional construction, ispositioned between the adjacent faces of drive pulleys 38 and I andis'adapted to be adjustably moved between the faces of these pulleys bymeans of screw shalt I4 which is suitably journalled and rotatable bymeans of a handle I6. Variable gear '12, as noted, is of conventionalconstruction and is provided to vary the speed ratios between the drivepulanism to chart 40 is in turn ordinarily designed to carry therotations from drive pulley 38in a oneto-one ratio to countershafts 54and B0 and thence to chart 40 whereby the chart will be caused to move adistance representing one foot of depth of the well for each rotation ofcountershaft60. By use of variable gear 12 any errors occurring in the.drive connection mechanism due to wearing of the parts can be correctedand compensated for in transmitting the rotations of'shaft 36 and pulley38 to the transmission mechanism, and the chance for error in the chartdrive is thereby eliminated.

As noted previously, the crown block pulley I4 engages in numerousrotations during drilling which are responsive to movements of thedrilling string other than those which represent increasing depth of thewell. For example, when the drilling string is drilling ahead, drillingordinarily continues for an interval of depth which 'is substantiallyequivalent to the length of the Kelly joint 28, which may be as much asthirty or forty feet or more. This movement of the drilling string,since it represents progressive A variable'gear 12, of I supplied bymeans of counter 56 which will be designated as the off-bottom counter.The details of the apparatus and the manner in which it functions willbe described hereinafter,

Since the essential element of the present in; vention comprises a novelformof selective transmission mechanism which is of somewhat complexcharacter in the modification illustrated deepening of the well, it isdesired to transmit.

to the recording chart. When, however, this I drilling interval iscompleted, a new sectionof drill pipe must be added, or it may bedesired to remove the entire drilling string from the well, as forexample, to changethe bit. The resulting reverse movements of thedrilling string from the well are, of course, transmitted to the crownblock pulley l4 and itsrotations are then transmitted to thetransmission mechanism connected e held at a position corresponding tothe attained depth, of the well, while the non-significant movements ofthe drilling string occur, and then to permit the chart to move aheadagain only when the drill bit begins to move downwardly in the well fromthe previously attained maximum depth. This maximum depth measurement issupplied by means of counter '62 which will be designated as themaximum. counter, while the *measurementsof the off-bottom movements ofI traveling block I8 or of. the drilling string are particularly inFigs. 4, 5 and 6, reference will be first had to the more or lesssimplified design 11- lustrated in Fig. 12 for the purpose of explainingthe functioning of such a transmission.

Numeral I00 represents a main drive shaft which is'rotative first in onedirection and then in the other for varying numbers of rotations. Mainshaft I00 is drivingly connected through a differential I02 toa firstdriven shaft I04, which is connected by a gear I06 to the ring gear I08of the differential, and to a seconddriven shaft I I0 which is connectedto one of the mitre gears I I2 of the differential and extends throughan axial'opening in the ring gear I08. The gear ratios are preferablysuch that each of the shafts I04 and IIO make one rotation for eachrotation of main shaft I00. The shafts I04 and H0 are threaded and theirends are journalledin a supporting frame II4. A threaded nut II Bcarrying a pointer I I1 is mounted on second shaft I I0 and held againstrotation by a guide bar II8 extending between the end members of frameII4. Thus rotation of shaft .I I0 causes nut I I6 to move back and forthalong shaft IIO depending upon the direction of rotation of the latter:A stop member I20 is positioned on the right hand end of guide bar I I8to positively limit the movement of nut H0 in the right hand direction.'A second nut I 22 carrying a pointer I24 is mounted on shaft I04 andheld against rotation by a second guide bar I26, so that it is alsoadapted to move along shaft I04 when it is rotated. For purposes ofexplanation, each of the threads will be taken to represent one foot oflineal movement corresponding to one rotation of main shaft I00 and alsoof the driven shafts I 04 and H0. A scale I28 bearing indiciarepresenting rotations of shaft I00, or feet, as the case may be, ispositioned parallel to shaft I 04 and in indicating re lationship topointer I24. Shaft I04 is provided with an outboard extension I30 whichis in frictional engagement with a symbolically illustrated frictionapplying member I32. A second scale I34 bearing indicia similar to'scaleI28 but reading in the reverse direction-is positioned parallel to shaftH0 and in indicating relationship to pointer I11.

This described transmission mechanism will function to selectivelyaccumulate only certain of',the rotations in one direction only of mainshaft I00, and .these selected rotations will be accumulated in shaft I04 and their cumulative total indicated on scale I28 by pointer I24. Theoperation is as follows: Sufficient friction is ap plied to shaft I04 bymeans of member I32 to make shaft I04 more difficult to rotate thanshaft H0. Nut I22 is initially positioned at the left hand end o'fshaftI04 at the zero position on scale I28, while nut H6 -is at its maximumright hand position against the stop member I20, corresponding to thezero position on scale I34. Assume main shaft I00 is rotated 'in theforward (clockwise) direction for fifty revolutions, nut I22 will movealong shaft I04 in the right hand direction to the position 50 on scaleI28. At the same t nge, since nut II6 is already at its maximum righthand position, shaft I'I0 is locked and cannot turn, and althoughfriction has been applied to shaft I04, it will, nevertheless, beselectively rotated by main shaft I through the differential I02, Nowassume main shaft I00 is rotated in the reverse directipn for twentyrotations. Both shafts. I04 and III! will .tend to rotate in the reversedirection, but be- Thus the indicia on the respective scales will nowshow that shaft I04 has turned fifty revolutions, or feet, in theforward direction while shaft I I0 has moved twenty revolutions or feetin the reverse direction. If these indications are considered torepresent well operations,

scale I28 will correspond to a showing that the maximum depth of thewell is fifty feet while scale I34 will show thatthe bit is at aposition twenty feet on-bottom. o it is. desired to again rotate mainshaft I00 in the forward direction, but is desired that no additions bemade to the reading on scale I28 until nut I I6 has returned to its zeroposition, that is, using the well drilling analogy, no increases indepth should appear until the drilling string is again on-bottom,irrespective of any intermediate. movements of the drilling string.Since nut H6 is now at the position, when main shaft I00 is rotated inthe forward direction, both driven shafts would ordinarily tend torotate in the same direction. However, because of the friction appliedto shaft I04, shaft IIO will be preferentially rotated by main shaft I00.acting through differential I02 until nut III;

has moved forward twenty threads and comes up against stop member I20.Immediately that nut IIB comes against stop member I20, the rotations ofshaft I00 will immediately be transferred by normal differential actionto shaft I04 which will again begin moving nut I22 in the right. handdirection from the 50 position as many threads as shaft I00 has turned,less the twenty turns necessary to bring nut H6 back to its zeroposition. Translating again to well drilling operationsfonly after thedrilling string is again on-bottom"'is the maximum depth recorder.released to record subsequent increases in depth.

It will also be apparent from the foregoing description, that so long asnut II6 remains away from stop I20, shaft 0 may be turned in eitherdirection by shaft I00, and as many times as desired, without affectingthe maximum attained position of nut I22. Only when the number of turnsof shaft H0 in the for-f ward direction brings nut IIG against stop I20,

will shaft I04 be released to move nut I22further in the right handdirection; Translating,

again to well drilling operations: So long as the drillingstring.remains off-bottom the string may engage in any number ofvertical movements of any length without afiecting the recording ofthe'maximum well depth. At the I same time every. change in position ofthe string relative to the bottom of the well will be continuouslyrecorded on the off-bottom register.

It will be apparent also that by the applica- 1 tion of friction toshaft I04 and the'described arrangement of the 'parts of thetransmission apparatus, shaft I04 will be constrained to rotate in onedirection only, the forward direc- Now, however,

tion, while shaft IIO will have limited rotation in the correspondingdirection and relatively unlimited rotation in the opposite direction.Stated briefly, the novel form of selective.

transmission above described comprises a main shaft which isintermittently rotative in opposite directions for varying numbers ofrotations, and means for accumulating selected rotations in onedirection only of the main shaft. The

accumulative means comprise first and second driven shaft, meansconstraining the first shaft to rotate in one direction only with themain shaft, a member limiting the rotation of said second driven shaftin said one direction while 1 permitting relatively unlimited rotationthereof in the opposite direction, and means, such as a differentialmember, cooperating between the driven shafts whereby the first drivenshaft is released for rotation with the'main shaft, only be describedhereinafter, by means of shaft 42a to the selecting differential 46which corresponds in function to differential I02 of the above describedtransmission. Shaff/ 42a carries a pinion 43 which is drivinglyconnected to ring gear 45 of the difierential 40 which transmits therotations of the main shaft through the corresponding initre gears 41and 49 to differential shafts 50 and 40, respectively. Shaft 50 is drivingly connected by chain drive 58 to countershaft 00 corresponding todriven shaft I04 above.

Shaft 60 drives maximum counter 62 and stub shaft 64., A pinion 5|mounted on stub shaft 64 turns a gear 50 which in turn drives a shaftcarrying a worm 51 which engages a gear 58 which is mounted on a shaftSI for turning the driving roll 63 for stri chart' 40, andfor un-.

winding it from ,feed roll .65. I-he gear ratios carried through thetransmission apparatus to the chart are preferably such that the chartismoved in the direction of the adjacent arrow through intervalscorresponding to one'rotation of main shaft 42 which in turn representsone foot of vertical movement of the drilling string,

as above explained The chart 40 is preferably marked with lines spacedat intervals of onefiftieth of an inch. That is, one inch of movement,ofthe chart represents 50 feet of depth of the well, and each rotation ofmain shaft 42 will move the chart one-fiftieth of an inch. Nu-' meral 61designates a representation of a conventional form of marking pen whichtraces on chart 40 the record of any test made by any 1 suitableinstrument, not'shown, of the character of 'the formation or thedrilling conditions in the well at the articular depths shown at theleft hand sideof the chart.

Shaft carries a brake drum 69 against which. is pressed a brake block IIconstructed of any suitable friction material. These elements cerrespondto the friction applying member I32, above described. The details of thebrake mechanism are shown in detail in Fig. 5 and consist of a curvedarm 13 which is pivotally attached by one end at 15 to some convenientportion of the transmission frame, not shown. Brake block 'H surroundsthe intermediate portion of arm 13 and is held in engagement withthe'surface of drum. 69 by connecting the free end of arm 13 to a coilspring 11 which is in turn connected to a convenient portion of thetransmission frame,

not shown. The tension of spring 11 isadjusted so that the proper amountof friction can be applied through drum 69 to shaft 60. I Counter 62 maybe any one of the conventional types of rev- Returning now todifferential shaft 48. This shaft is, connected by a sprocket and chaindrive 52 tocountershaft 54 which drives counter 56, referred to as theoff-bottom counter, equivalent to scale I34 and pointer H1, above. Thiscounter is similar in construction to counter 62 except that it isprovided with stop mechanism which, while permitting rotation of theindicia wheels in either direction when the number of revolutionsrecorded thereon is greater than zero,

- prevents any rotation of the indicia wheels from the zero position inthe opposite direction toward the 9--9-9 position. That is, the indiciawheels are free to move forwardly from the zero position to any positionup to that representing the maximum recording capacity of the countershown,

namely, 999, and in the reverse direction between this maximum and thezero position, but cannot move in the opposite direction from the zeroposition. This stop mechanism corresponds to stop member 120, of theabove described simplified transmission, and consists of 8. lug 19 whichis aflixed to the zero marking on the left hand indicia wheel 83 andextends radially therefrom. Lug l9 cooperates with a second lug 6imounted inside the counter case and extending toward indicia wheel83 andunder lug [9 (Fig.6). Thus while indicia wheel 83 is free to rotatecounterclockwise from lug 8i, that is in the forward direction to themaximum counting capacity of the counter, namely 999 revolutions, and inthe opposite direction to any position corresponding to any number ofrotations greater than zero, it can never move past the counters zeroposition, and the rotation of shaft 54 is thus locked against rotationbeyond this position.

The manner in which the selective transmission just described functionsto drive the chart 4U from the movements of the drilling string will nowbe described.

For purposes of this illustrative description, reference being hadparticularly to Figs. 1, 4, 5 and 6, we will assume that drillingoperations are about to begin, bit being at the top'of the ground. Inaccordance with conventional practhis counter is designed to turn in theopposite direction to counter 62 'in'measuring distances off-bottom.Drilling is now begun. As the drilling string 20 moves downwardly in thewell,

off-bottomtraveling block l6 moves correspondingly downward, rotatingcrown block pulley l4 in a direction corresponding to such movement, anddrives measuring wheel H which in turntransmits its rotations,representing the footage of downward movement, to main shaft 42 of theselective.

mechanism. The corresponding forward rotation of main shaft 42 istransmitted through differentials 44 and 46 to maximum counter 62, whichregisters the progressively increasing depth of the well, and at thesame time drives chart 40 which has also been started from its zeroposition when drilling began. The depth reading on chart 40 willcorrespond to the depth reading appearing on counter 62, the chartmoving an interval corresponding to one foot of depth for each rotationof shaft 60 and for each increase of one digit in the reading on counter62. These movements continue until the drilling has proceeded for aninterval-substantiallyequal to the length of the kelly 26, say 40 feet.However, since I measurement is normally begun when the lower end of thedrill bit begins to descend below the level of the top of the rotarytable, the total measurement recorded after the full length of the kellyha been drilled will be 40 feet, the length of the kelly, plus thelength of the bit stem and collar, which. is, say, 20 feet, or a totallength of 60 feet will be recorded. Counter 62 and chart 40 will eachrecord 60 feet as the maximum depth of the well. Counter 56 will, ofcourse, continue to show a zero reading since it is locked in thisposition as above described. It now becomes necessary to add anotherjoint of drill pipe, say 40 feet in length, in order to continuedeepening the well. To perform this operation, the drilling string mustbe drawn upwardly out of the well until the lower end of the kelly isabove the rotarytable 32. off the bottom a distance somewhat greaterthan the length of the kelly so that the upper end of drill collar andbit may be grasped by the usual slips and held so that the kelly may beunscrewed. Assume that this,reverse movement is 50 feet. Traveling blockIE will of course move upward a similar distance and producescorresponding reverse rotations of crown block pulley I 4, which will beimmediately transmitted to the selective transmission in the form ofreverse rotations of main shaft 42 which are in turn transmitted tocountershafts 54 and 69. However, since friction has been applied toshaft 60 through the medium of brake 68, and since shaft 54 is free torotate in the reverse direction, differential 46 will become operativethrough the friction in shaft 60 to selectively rotate shaft 54 in thereverse direction while shaft 60 remains stationary. Shaft 54 will,therefore, rotate the wheels of counter 56 in accordance with thereverse rotations of main shaft 42 until the counter wheels register 50feet, A

the distance through which the traveling block and the drilling stringhave moved upwardly in the well. The reading on counter 56 of 50 feet isthe present off-bottom position of the bit,

traveling block are, of course, transmitted to the crown block pulley I4and thence to the transmission mechanism whereby they produce corre-This requires that the bit he lifted drilling string and in order to dothis, the travel-- ing above the door of the derrick, traveling block IEwill necessarily have, returned to thesame position it had previouslyattained when it lifted the drilling string and kelly out of the well,name'- ly 50 feet off-bottom, and counter 56 will accordingly againcarry a reading of 50 feet. Now it is necessary to replace the kelly atthe top .of the ing block must lower the drilling string, now in-.cluding the new joint of pipe, into the well until only the upper endprotrudes above the rotary table. Assume this downward movement to be 40feet. The reading of counter 56 will there-' upon be reduced by thecorresponding downward movement of the traveling block and will now read10' feet, the present distance ofl-bottomof the bit. Traveling block itis now disconnected from the upper end of the drill pipe and echnectedto the kelly which is swung into place and screwed to the upper end ofthe drilling string. When this operation has been completed, travelingblock IE will have come to rest again,'at an upward position in thederrick above the upper end of the added. joint of drill pipe equal tothe length of the kelly, namely 40 feet, and this additional upwardmovement will have been recorded on counter 56, which will riow registeran oil bottom measurement of 50- feet, although, as noted, the actualposition of the bit will have remained unchanged at 10 feet off-bottom.Now, as the entire drilling string is lowered in the well to bring thebit on-bottom, traveling block it will move downwardly only 10 feet toattain the on-bottom position, and the correspondingrecording on counter56 will bring its reading down from feet to 40 feet. If now, drillingwould be permitted to proceed, no additional footage, rep-.- resentingthe deepening of the well, would be recorded on maximum counter 82,since counter 58 had not yet reached its zero position so as to releasecountershaft 60 to turn counter 62. It is necessary, therefore, toprovide some means for returning the reading of counter 58 tozero whenthe bit has actually touched bottom, so that shaft 89 may be releasedand immediately 'begin recording on counter 62 the further downwardmovement of the bit from the previously attained maximum depth. Inperforming thisoperatlon of returning counter 56 to its zero reading,what is actually done, is to subtract from the reading of counter 56 thefootage representing the length 0 of tlr e'new joint of drill pipe whichhas been added to the drilling string. This operation is performed bymeans of auxiliary differential 44 which has been previously advertedto,and itsconstruction and function will now be described 65. indetail.f As illustrated particularly in Fig. 4, auxiliary differential 44 is ofmore or less conventional construction and is arranged between maindrive shaft 42 and selecting differential 48 so that shaft 4: drivesdirectly throughthe mitre gears 81 of dlflerential 44 to differential 48without variation inthe movements imparted to differential 46 exceptpossibly to reverse the direction, of rotation of shaft 42a whichconnec'tsthe two diflefen- .78

tials. This reversal 'of rotation is, 'of'course, again correctedby thevarious gearand drive connections in differential so that the rota--tions of the driven shafts 48 and"!!! correspond in the desired mannerto the vertical movements of the drilling string. The spider 89 of thediffer- 1 '62 which represent vertical movements. of the drillingstring, ring'gear 9| remains stationary.

- When, however, it is desired to subtract the additional footagerepresented by the added joint of drill pipe, the handle 91 is turned,rotating ring gear 9| which in tum' rotates countershaft 5 4, as thisshaft is still free to turn toward the zero position, since its readingis 40'feet, although the bit is actually on bottom. As many rotationsare thus made as are necessary to equal the footage of the added sectionof drill pipe. Since, as noted, this added section was 40 feet long,when the number ofturns of auxiliary differential 44 equivalent to thisfootage hasbeen made, 40 feet will have been subtracted from the readingof counter 56 and its reading will become zerowhich isthe true reading,since the bit is on bottom. Now when drilling is, again begun,

causing corresponding downward movement of the traveling block l6, thismovement will be transferred through diflerehtial 46 to shaft 60 becausecounter 56 has now become locked at its zero position and counter 62 andchart 40 will accordingly begin' registering the increasing depth. I X

Y The aforedescribed operations, including-the corrective rotations ofauxiliary differential 44 are repeated for each! addition of sections tothe drilling string, and it tei shaft 60 will accumulate only thosedownward movements of traveling block l6 which represent progressivelydownward movements of the bit. These accumulated movements will beregistered on maximum counter 62 and on chart 48. which will be moved inexact accordance thereand friction brake 68 toselectively transmit tocounter 82 and chart 40 only those movements of main shaft 42 whichcorrespond to, progressive- I ly downward movements of the drill bit.

It will be understood that auxiliary'diflerential 44 may be employedeither for adding or subtracting corrective rotations to the shafts i4and 60, depending upon whether sections of drill pipe 'are being addedto, or removed from, the drilling string, or to correct for errors inthe length of the drilling string. By the form of'its construction andits arrangement auxiliary diflerential can be employed to introducerotations into the transmission mechanism while main shaft 421s rotatingor stationary, and the rotations thus introduced will correspondinglyalter the reading i of counters 58 and 82 independently of manure-"- berof rotations already made by main shaft 42;

Fig. 7 illustrates a modified form of off-bottom counter 58 which, byits construction, combines-in asingle piece of equipment, the functionsof the off-bottom counter and of the auxiliary differential 44. 'In'this modified form, the ends of shaft 54 which extend beyond each end ofthe case I09 of the counter, which will be designated 98, are Journalledin bearings 9.9 and which-is attached a handle will beapparent thatcoun-' llll which are shaft II carries ahandle H9. Counter 98 func- Itions normally in exactly the same manner as counter 56 in the earlierdescribed modification.' However, when corrections in the reading ofcounter 98 are to be made to account for the adding-in of sections ofdrill pipe to the drilling string, by turning handle H9 in the properdirection, the case I09 of the counter will be retated and will changethe reading of the counter in accordance with the number of turns made.

The turning of the case will effect the same subtraction in the counteras is effected by the operation of auxiliary differential 44, aspreviously described. It will be understood that various other forms ofapparatus may be similarly designed for use with the transmissionmechanism of this invention to introduce the corrections occasioned bythe additions to the length of the drilling string. I

The aforedescribed chart drive system maybe employed as described toeffect a selection from all of the movements of traveling block I6 ofonly those particular movements which are to be em-' ployed to drive thechart, or particular movements of the drilling toolswhich are coupled tothe chart drive may be pre-selected, as by means of the apparatusshownin my former Patent No. 2,166.212, or in my co-pending applicat onSerial .No. 279,422. filed June 16, 1939, now U. S. Patout No.2,221,767, Nov. 19, 1940, or by any other ployed to drive such othermechanism in accordance with the downward movement of the drill. This)auxiliary drive is particularly useful for driving mechanism such asdrilling rate indicators, generally illustrated at I54 in Fig. 8, whichis illustrated as driving marking pen 61 to trace the record of drillingrate against depth on chart 40.

the switching arrangement will be described hereinafter in connectionwith the detailed de scription of this new modification.

Referring to Figs. 8 to 11, a normally open switch consisting of adetentarm I34 and a fixed arm I36 are mounted inside the case of counter56 and detent arm I34 is arranged so as to be depressed into contactwith fixed arm I36 by pres- .sure from lug 19 when indicia wheel 83attempts to move past its zero position toward the 9--99 position of thecounters. Wire leads I33 and I35 connect arms I34 and I36, respectively,in circuit with a group of relays I31, I38 and I39, and with a suitablecurrent source such as a battery I40. The relays control switche I4I,I42 and I43, re-

spectively. Relay switch MI is connected by leads I44 and I45 in circuitwith a battery 'I46 and- I with a solenoid I41 which controls theoperation with a pawl I49 which is hingedly attached to the case ofcounter 62. The pawl I49 cooperates with ratchet wheel I48 so as topositively prevent reverse rotation of shaft 60. That is, shaft 60 cannowmove only in the forward direction representing progressive downwardmovement of the Figs. 8, 9, 10 and 11 illu'strate a modified form of thechart drive of this invention. In this modified form, the stop member incounter 56, which normally functions as a. control for the movements ofshaft and counter 62, includes an electrical switching arrangement whichis em ployed to automatically control and perform a number of usefuloperations. Primarily it is employed to automatically control themovements of shaft 60, by actuating an electric control for brake 68,which automatic'ally releases brake 68 and allows shaft 30 to rotateforwardly when the indicia wheels of counter 56 attempt to movebeyondthe zero position. and automatically sets brake 63 when the reading of.counter 56 is .greater than zero, irrespective of the direction ofrotation of shaft 54. Other useful functions of drill. The free end ofbrake arm 13 is pivotally attached to the end of the armature I50 ofsolenoid I41, and an extension of armature I50 is connected to an end ofcoil spring 11 which is now arranged to normally hold arm 13 and brakeblock 1| out of engagement with brake drum 69.

The electric control of brake-.63 operates as follows: When the drillbit is on bottom, counter 56 will register zero on all its wheels, aspreviously described. At the instant further drilling begins,countershaft 54 will tend to rotate beyond the zero position and theinitial rotary movement will cause lug 19 to depress arm I34 and closethe counter switch which will in turn immediately open relay switch I4Icutting off the flow of current in the windings of solenoid I41.Armature I50 will thereupon be released anclwill be pulled upwardlybythe tension of spring 11 and will draw brake block 1I out of brakingengagement with brakedrum 69, and releases shaft 60 for rotation. Aslong as the drill continues to move downwardly in the well. shaft 60will remain free to rotate the wheels of counter 62 and the drive tochart 40 in accordance with the downward movement of the bit. When,however, the bit is lifted off-bottom the corresponding reverse movementof the wheels of counter 56 will relieve the pressure of lug 19 ondetentarm I34 and break its contact witharm I36. This action will in turncause relay switch I M to close'actuating solenoid I 41 to draw armatureI 50 down and thereby pull brake'block 1I into braking engagement withdrum 69 thus eifectivelystopping anyrev'erse movement of countershaft60. However, since the initial reverse movement of.

- the bit would normally tend to cause correspond ing reverse movementof shaft '50, as well as of shaft 54, since the brake on shaft 60 is notyet engaged, then, in order to preventanysuch' re versal of shaft 60,and to permit preferential reversal of shaft-54 so as to cause theswitch in counter 56 to actuate and set. the brake on shaft 60, ratchetI48 and pawl I49 are provided to cooperate to prevent any reversemovementof shaft 60, and thus enforce the desired preferential rotationof shaft 54 which results in setting of the brake 6 8. when the brakehas thus become set, no movements of the traveling block I6 occurringwhile the bit is off-bottom can affect counter 82 until-such movementsoccur as will bring counter 56 back to the zero position so'as to againclose the circuit to relay I31 and release brake 88.

Relay I38 is employed to operate a lamp II.

and bell I52 which are arranged in parallel in;

ranged to close this circuit when the switch formed byarms I34-and I38is closed. That is,- when the bit is on bottom. Closing of switch I42.lights up lamp HI and rings bell I52, thus giving the drill operatorboth a visible and an audi ble signal when the bit is on bottom. Thelamp IN is ordinarily allowed to remain lighted as circuit with switchI42. Relay switch I42 is ar-' -l0 with themain shaft in' one directiononly cdrresponding to downward progress of said drilling string in thewell and to render said second driven shaft normally preferentiallyrotatable by said main shaft, and means cooperating with said seconddriven shaft to limit its rotation with then main shaft in said onedirectionwhile permitting relatively unlimited rotation thereof in theopposite direction. '1 Y 2. In combination with a drilling string and a-welldepth exhibiting means adapted to exhibit the depth of the well inaccordance with the downward progress of said drilling string in thewell, a drive for said exhibiting means comprislong as, the bit is onbottom or drilling ahead.

Bell I52 may be cut-off by means of aswitch IE3 after it has givenwarning that the bit has touched bottom.

Switch I43 is also arranged to close when the switch in counter 56closes, and is connected in circuit with an instrument such as aconventional drilling rate indicator I54 which is shown as operating pen61. The circuit connects relay switch I43 with a conventional pencontrol when reverse movements of the drilling tools occur, opens relayswitch I43 and stops pen 6'! at exactly the point it occupied at theinstant chart 40 has likewise stopped.

It willbe seen, therefore, that the switch in counter 58, in addition toaiding in the automatic selection of the movements of the drilling toolsto be transmitted to chart drive 40, may be employed for numerous otherfunctions related to the position of the drill in the well. In additionto those specifically enumerated above, the

' switch may be employed, through the use of additional relays, in othercapacities and for other uses which willbeapparent to those-skilled inthe art to which this invention appertains.

It will be apparent that numerous modifications and alterations may bemade in the details of construction and in the form of arrangement ofthe parts of this invention without departing from the scope of theappended claims,

What I claim and desire to secure by Letters Patent is: t

1. In combination with a drilling string and a well depth exhibitingmeans adapted to exhibit ing, a main drive shaft driven from saiddrilling string and reversibly rotative in synchronism withcorresponding measured-vertical movementsof said drilling string, afirst driven shaft drivingly'connecting said main drive shaft to saidexhibiting means, a second driven'shaft driven by said main drive shaft,a differential member connecting said main. drive shaft to said firstand second driven shafts, means operative upon said-first driven shaftto constrain its rotation with the main shaft in one direction onlycorresponding to downward progress of said drilling string in the welland to render said second driven shaft normally preferentially rotatableby said main shaft, and a revolution counter reversibly driven by saidsecond driven shaft and including means for preventing rotation of saidsecond driven shaft insaid one direction when said counterattains itszero reading in that direction.

3. In combination with a drilling string and a well depth exhibitingmeans adapted to exhibit the depth of the well in accordance with thedownward progress of said drilling string in the well, a drive for saidexhibiting means comprising, a main drive shaft driven from said drillinstring and reversibly rotative in synchronism with correspondingmeasured vertical'movements' of said drilling string, a first drivenshaft drivingly connecting said main drive shaft to said exhibitingmeans, a second driven shaft driven by said main shaft,-and meanscooperating between said first and second driven shafts and said maindrive shaft whereby said first driven shaft is constrainedto drive saidexhibiting means in one direction only corresponding to progressivedeepening movements of said drilling tools in the well, and auxiliarymeans for rotating said' driven shafts independently of said main driveshaft. V

the depth of the well in accordance with the downward progress of saiddrilling stringin the well, a drive for said exhibiting means,comprising, a main drive shaft driven from sale? drilling string andreversibly rotative in synchronism with corresponding measured vertical.movements ofv said drilling string. a first driven shaft drivinglyconnecting said main drive shaft to said exhibiting means, a' seconddriven shaft driven by said main drive shaft, a differential memberconnecting saidmain shaft to said first and second driven shafts, meansoperative upon said first driven shaft to constrain its rotation 4. Incombination with a drilling string and a well depth exhibiting meansadapted to exhibit .the depth of the well in accordance with thedownwardprogress of said drilling string in the well, a drive for saidexhibiting means comprismg, a main drive shaft driven from said drillinstring and reversibly rotative in synchronism with-correspondingmeasured vertical movements of said drilling string, a first drivenshaftdrivingly connecting said main, drive shaft to said exhibitingmeans, a second driven shaft driven by said main shaft; and shaftselecting me'ans' cooperating betweensaid first and second driven shaftsand said main drive shaft whereby said first driven-shaft is selectivelyconstrained to drive said exhibiting means in the direction .onlycorresponding to progressive depending movements of said drilling toolsin the well and auxiliary means for altering the accumulated rotationsof said driven shafts independently of said main drive shaft.

with corresponding measured vertical movements of said drilling string,a first driven shaft drivingly connecting said main drive shaft to said.

exhibiting means, a second driven shaft driven by said main drive shaft,a differential member connecting said main shaft to said first andsecond driven shafts, means operative upon said first driven shaft toconstrain its rotation with the main shaft in one direction onlycorresponding to downward progress of said drilling string in the welland to render said second driven shaft normally preferentially rotatableby said main shaft, and means cooperating with said second driven shaft,to limit its rotation with the main shaft in said one direction whilepermitting relatively unlimited rotation thereof in the oppositedirection, and an auxiliary differential member cooperating with saidfirst'and second driven shafts for altering the accumulated rotationsthereof independently of said main drive shaft.

6. In combination with a drilling string and a well depth recordingchart adapted to record the depth of the well in accordance with thedownward progress of said drilling string in the well, a drive for saidchart comprising, a main drive shaft driven from said drilling stringand reversibly rotative in synchronism with corresponding measuredvertical movements of said drilling string, a first driven shaftdrivingly connecting said main drive shaft to said chart, said firstdriven shaft being releasably constrained to rotate with said main shaftin one direction only corresponding to said downward movements of saiddrilling string, a second driven shaft reversibly driven by said mainshaft, means limiting the rotation of said second driven shaft in saidone direction while permitting relatively unlimited rotation thereof inthe opposite direction,

tion, and means associated with said stop means and operative upon thelimitation of rotation of said second driven shaft thereby to releasesaid brake.

8. Apparatus according to claim 7 including, an electrically controlledrelease means for said brake, and an electrical switch means in circuittherewith and actuable by said stop means to release'said brake.

9. Apparatus for recording well depths during drilling comprising, adrilling string movable vertically in a well, a; traveling block forsuspending the drilling string and movable vertically tical movements, ameasuring wheel driven by and means cooperating between said first andsaid one direction only upon the attainment by said second driven shaftof the limit of its rotation in said one direction.

7. In combination with a drilling string and a well depth exhibitingmeans adapted to exhibit .the well depth in accordance with the downwardprogress of said drilling string in the well, a drive for saidexhibiting 'means comprising, a main drive shaft driven from saiddrilling string and reversibly rotative in synchronism withcorresponding measured vertical movements of said drilling string, afirst driven shaft drivingly connecting said main drive shaft to saidexhibiting means, a second driven shaft driven by said main drive shaft,a differential member connecting said main shaft to said first andsecond driven shafts, means constraining said first driven shaft torotate with said main drive shaft in one direction only corresponding todownward progress of said drilling string in the well, releasable brakemeans ingly connect said mechanism to said said pulley for measuring thevertical movements of the traveling block, a selectivetransmissiondriven by said measuring wheel in synchronism, with themeasured vertical movements of said traveling block, a depth recordingchart releasably driven by said selective transmission, said selectivetransmission including selecting means arranged to be operative ony bythose measured vertical movements of the traveling block correspondingto progressive deepening of the well to drivingly connect said mechanismto said chart, well logging apparatus for placing well logging data onsaid chart, and control means operative by said selecting means in saidtransmission mechanism for causing said logging apparatus to place itsrecord on said chart only when said chart is being driven by saidmechanism.

10. In combination with a drilling string movable vertically in a well,a strip recorder chart bearing footage indicia representative of thedepth of said well and adapted to be driven in synchronism with thedownward progress of said drilling string in the well, apparatus forplacing continuous records of drilling operations on said chart, and achart drive, comprising, a selective transmission mechanism releasablyconnecting said drilling string to said chart, said transmissionmechanism including selecting means arranged to be operative only bythose downward movements of the drilling string which constituteprogressive deepening of the we?! to driv- Lhart, and control meansoperative by said selecting means to thereby cause said records to beplaced on said chart by the recording apparatus only when said chart isbeing driven by said mechanism.

11. In combination with a drilling string and a well depth registeradapted to register the depth of a well in accordance with the downwardprogress of the drilling string therein, a drive for said registercomprising, a main drive shaft driven from the drilling string, adiffere' .1 connected to said main drive shaft, first and secondrevolution counters driven by said main drive shaft through saiddifferential, means constraining said first counter to cumulativelycount revolutions of the main drive shaft in one direction onlycorresponding to downward progress of said drilling string, retardingmeans operative upon said first counter whereby said second counter isreversibly driven by the main shaft normally preferentially relative tosaid first counter, and means to lock said second counter againstrotation in said one direction upon attainment of its zero reading inthat direction to thereby cause further rotations of said main shaft inthat direction to preferentially drive said first counter.

12. In combination with a drilling string adapted to 'move vertically ina well and a well depth recording chart adapted to be driven inaccordance with the downward progress of the drilling string in th well,a drive for said chart comprising, a main drive shaft driven from thedrilling string, a differential driven from said shaft and having onebranch drivingly connected to said chart, means constraining the-chartto move in one direction only corresponding to downward progress of saiddrilling string, a revolution counter connected to said main shaftthrough a second branch of said differential and reversibly driventhereby normally preferentially relative to said chart, and means tolock said revolution counter against rotation in said one direction uponattainment of its zero reading in that'direction to thereby causefurther rotations of said first branch in that direction to preferentially drive said chart.

13. In combination with a drilling string and a well depth exhibitingmeans adapted to exhibit the depth of the well in accordance with thedownward progress of the drilling string in deepening the well, a drivefor said exhibiting means, comprising, a main drive shaft driven fromsaid drilling string and reversibly rotative in synchronism withcorresponding measured vertical movements of said drilling string, afirst driven shaft drivingly connecting said main drive shaft tosaidexhibiting means and constrained to rotate in one direction onlycorresponding to downward movements of said drilling string, a seconddriven shaft reversibly driven by said main shaft normallypreferentially relative to said first drivon shaft, and means actuableby pro-determined limitation of the rotation of said second shaft insaid one direction to produce preferential r0- tation of said firstdriven shaft in said direction.

14. Apparatus for recording well depths during drilling, comprising, adrilling string adapted to move vertically in a well, a well depthrecorder, a drive for said recorder, said drive comprising, a main driveshaft driven from the vertical movements of said drilling string, adifferential driven from said shaft and having a first branch drivinglyconnected to said recorder, means constraining said recorder to move inone direction only corresponding to downward progress of said drillingstring, a second branch of said differential reversibly driven by saidmain shaft normally preferentially relative to said recorder, and

means to lock said second branch against rotation in said one directionupon attainment of a pre-determined limit of rotation in that directionto thereby cause further rotations of said first branch in thatdirection to preferentially drive said recorder.

15. In combination with a drilling string and a well depth registeradapted to register the depth of a well in accordance with the downwardprogress of the drilling string therein, a drive for said register,comprising, a main drive shaft driven from the vertical movements ofsaid drilling string, a differential member connected to drillingcomprising in combination with a drill-' ing string movable verticallyin a well, a well depth recording means, a transmission mechanismoperative only by thosedownward movements of the drilling string whichcorrespond to. progressive deepening of the well to drivingly connectsaid drilling string to said recording means, and an auxiliary adjustingmechanism foraltering the position of said transmission mechanism tocompensate for changes in length of said drilling string;

JOHN T. HAYWARD.

